1. Field of the Invention
The present invention relates to an alarm mark structure of a micro-differential pressure gauge, and more particularly, to a pointer gauge structure having a mark member which is coupled to a recess of a transparent casing.
2. Description of the Prior Art
A conventional gauge, such as a micro-differential pressure gauge or a pressure gauge, includes a pointer therein. The pointer is rotated according to the pressure. In conjunction with a numeral scale plate in the gauge, the user can read the value. In general, the gauge is set with a security value. For the user to know whether or not the pointer is in the range of safety, the gauge is provided with a safety mark. The conventional mark is secured on an outer edge of the gauge. When the gauge has to be installed in an embedded way, such as in a hole of a flat board of an apparatus, the mark cannot be attached to the gauge because the circumferential edge of the gauge is tightly against the flat board. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve this problem.